Fixes #133 - Correct assertions

- ASSERT_TRUE( isHorizontal() )
- ASSERT_FALSE( isVerticalRightToLeft() ) and ASSERT_FALSE(
  isVerticalLeftToRight() ) in order to check multiple code paths
- ASSERT_EQ( 1, errorCount() ) for safety
- Use convenience assertEquals function to save space
- Comments wrapped to 80 columns but otherwise unchanged